Omnidirectional Adjustment-oriented Positioning Device of Office Chair Armrest

ABSTRACT

An omnidirectional adjustment-oriented positioning device of an office chair armrest includes two parallel inner links pivotally connected between an armrest rotation fixing unit and a rotation base. The inner links are enclosed in outer links to form a parallel four-link swing link component. The rotation base is axially disposed at a pad. An armrest component capable of horizontal rotation and displacement is disposed at the armrest rotation fixing unit. Inner and external wheel components with bevel gears meshing with each other are disposed between upper ends of the outer links and the armrest rotation fixing unit. Positioning gears which mesh with each other are disposed at the armrest rotation fixing unit. A positioning wheel is mounted at the armrest rotation fixing unit and rotatable such that a rotation component for rotating the inner wheel component abuts against the inner wheel component and thus drives the positioning wheel to move outward.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an omnidirectional adjustment-oriented positioning device of an office chair armrest, characterized in that: a swing link component of a parallel four-bar linkage device is mounted on each of the two sides of a pad; an armrest component capable of forward, backward and rotational positioning is disposed at an upper end of the swing link component such that the positions of armrests can be adjusted vertically, forward, backward and laterally while keeping the horizontal posture of the armrests; and a device which is easy to adjust and exercise positioning control is disposed at the pivotal connection point of the armrest component and the swing link component.

2. Description of Related Art

Armrests disposed on the two sides of a conventional office chair are stationary, as the armrests are fixed to the two sides of a pad from below and thus cannot be adjusted any more in whatever way. However, the appropriate heights of the armrests which users' forearms rest on depend on the users' body heights. In view of this, armrest devices capable of adjusting armrest height or even capable of adjusting the positions of armrests forward and backward are commercially available, such that users of different heights can put their forearms on the armrests with appropriate heights and forward and backward positions.

In addition to body height, users vary in terms of waistline, as the number of obese users and skinny users is on the rise. If the positions of the armrests on the two sides of an office chair are fixed rather than adjustable, for example, laterally, the forearms of full-figured users may not rest comfortably on the armrests which are inevitably closer to the bodies of the full-figured users than the bodies of users with normal body weights, whereas the forearms of skinny users must tilt outward in order to rest on the armrests which are inevitably farther from the bodies of the skinny users than the bodies of users with normal body weights. Hence, the aforesaid two situations occur, because the positions of the armrests cannot be adjusted laterally.

Therefore, the positions of armrests are not only adjustable vertically, forward and backward, but also adjustable laterally, such that the positions of the armrests can be adjusted in a three-dimensional manner to thereby ensure the comfort of the users forearms which are resting on the armrests.

However, armrest devices capable of three-dimensional adjustment have disadvantages. First, their assembly process is never smooth for structural reasons. Second, its adjustment process must be carried out stage by stage and direction by direction and thus never occurs at one go; hence, it is inconvenient to carry out the adjustment process. Third, due to poor design of adjustment positioning structures, not only are the armrest adjustment devices rarely operated ergonomically, but a parallel four-bar linkage device which supports the upper portion of the armrest may also clamp the users' fingers inadvertently and thus has to be enclosed by a casing for shielding sake; however, the shield is seldom satisfactory but definitely adds to structural complexity and causes difficulties to the assembly process, not to mention that it compromises the appearance of the device. One of the aforesaid armrest adjustment devices is disclosed in US20150157131A.

SUMMARY OF THE INVENTION

To overcome the aforesaid drawbacks of conventional office chair armrests in terms of adjustment of positions, for example, the low likelihood of ergonomic operation of an armrest adjustment device and the hassles of enclosing the armrest adjustment device in a casing for shielding sake, the present invention provides an omnidirectional adjustment-oriented positioning device of an office chair armrest, characterized in that: an armrest component axially disposed at the lower end of a swing link component of a parallel four-bar linkage device and axially disposed on each of the lateral sides of the chair so as to be rotatable, such that the armrest component maintains its horizontal posture and are able to swing upward and downward, wherein the armrest component is inherently capable of horizontal rotation as well as forward and backward displacement, wherein two parallel inner links of the swing link component are enclosed in two opposing outer links, wherein an inner wheel component driven by a rotation component to abut against and drive an external wheel component to move outward is disposed at the pivotal point of the armrest component and the upper ends of the outer links, such that a positioning wheel driven under an elastic force and an armrest rotation fixing unit pivotally fixed to upper ends of the inner and outer links abut against each other. As a result, positioning gears otherwise meshing with each other are separated, and in consequence the armrest component can undergo three-dimensional adjustment.

The technical solution employed to solve the technical problems addressed by the present invention is described below. An armrest component is axially disposed at an upper end of an armrest fixing unit and is rotatable. An armrest component capable of horizontal rotation and forward and backward displacement and thus positioning is disposed at the upper end of the swing link component of the parallel four-bar linkage device. The swing link component comprises a rotation base pivotally disposed on the armrest fixing unit and having an upper end provided with a pivot portion and an armrest rotation fixing unit pivotally fixed to an armrest component and having a lower end provided with a pivot portion, wherein an inner link is pivotally connected between and slightly outside the two pivot portions of the armrest rotation fixing unit and the rotation base, wherein two sides of a middle of each of the two pivot portions are pivotally fixed in place to enclose an inner link and two parallel opposing outer links. A bump portion and a rotation-proof recess being substantially polygonal and annular and having a bottom which an oblong hole is disposed on are centrally disposed on a lateral surface of the pivot portion of the armrest rotation fixing unit. An inner wheel component and an external wheel component each have two opposing surfaces which annular continuous bevel gears meshing each other are disposed on are disposed in the rotation-proof recess. The inner wheel component is fitted around the bump portion and thus rotatable. The external wheel component is slidingly received in the rotation-proof recess to thereby be able to move axially only. A positioning wheel, which slidingly engages with the outer links and thrusts under an elastic force, abuts against the external wheel component. Positioning gears, which are annular and resiliently mesh with each other, are disposed at a pivot portion of the armrest rotation fixing unit and the positioning wheel. A rotation component is pivotally fixed inside the armrest rotation fixing unit. The rotation component has an inner end for rotating the inner wheel component and an outer end which can be extended and thus moved by the users. The inner wheel component rotates to thereby cause the bevel gears to drive the external wheel component to move outward, such that the positioning wheel withdraws together with the external wheel component. The positioning wheel and the pivot portion of the armrest rotation fixing unit operate to separate the positioning gears otherwise meshing with each other, such that the swing link component can rotate and swing upward and downward, so as to adjust the forward, backward, lateral and vertical positions of the armrest component.

The advantages of the present invention are described below. A swing link component enables an armrest component to perform vertical adjustment and still maintain horizontal posture. A positioning device disposed between outer links and an armrest rotation fixing unit renders vertical adjustment ergonomic and convenient. Since the inner links of the swing link component are hidden inside the outer links, a parallel four-link mechanism of the swing link component looks neat and is unlikely to clamp the user's fingers inadvertently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an omnidirectional adjustment-oriented positioning device of an office chair armrest according to the present invention;

FIG. 2 is a partial exploded top schematic view of an armrest component according to the present invention;

FIG. 3 is a partial exploded bottom schematic view of the armrest component according to the present invention;

FIG. 4 is a schematic view of a horizontal rotation adjustment of the armrest component according to the present invention;

FIG. 5 is a schematic view of forward and backward position adjustment of the armrest component according to the present invention;

FIG. 6 is an exploded schematic view of rotating the lower end of a link component according to the present invention;

FIG. 7 is a schematic view of rotation adjustment of a rotating link component according to the present invention;

FIG. 8 is an exploded schematic view of the rotating link component according to the present invention;

FIG. 9 is a partial enlarged schematic view of the upper end of the rotating link component according to the present invention;

FIG. 10 is a side partial cross-sectional schematic view of the omnidirectional adjustment-oriented positioning device according to the present invention; and

FIG. 11 is a schematic view of operation of vertical adjustment of the armrest component according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 and FIG. 2, the present invention provides an omnidirectional adjustment-oriented positioning device of an office chair armrest, essentially comprising: an armrest fixing unit 1 fastened to an office chair pad laterally; an armrest component 2 for supporting a user's forearm; and a swing link component 3 equipped with a parallel four-link mechanism and connected between the armrest fixing unit 1 and the armrest component 2. Referring to FIG. 2 and FIG. 3, the armrest component 2 essentially comprises an armrest 21, a cover 22, a forward and backward displacement positioning device 23 and a horizontal rotation positioning device 24. A space 210 is concavely formed on the back of the armrest 21 to contain the forward and backward displacement positioning device 23 and the horizontal rotation positioning device 24. The space 210 is covered with the cover 22. The forward and backward displacement positioning device 23, the horizontal rotation positioning device 24 and the cover 22 are penetrated by screws to allow the armrest component 2 to be pivotally fixed to an armrest rotation fixing unit 32 disposed on the top end of the swing link component 3, such that the armrest component 2 can be adjusted to undergo horizontal rotation and positioning (shown in FIG. 4) and adjusted to undergo forward and backward displacement and positioning (shown in FIG. 5) above the swing link component 3.

A substantially L-shaped horizontal end of the armrest fixing unit 1 is fixed to the chair pad laterally. An axially-positioned bearing hole is disposed on the end surface of a vertical end of the armrest fixing unit 1. The lower end of a rotation base 31 disposed at the lower end of the swing link component 3 is axially disposed in the bearing hole, such that the rotation base 31 (and thus the swing link component 3) can be rotated and positioned on the armrest fixing unit 1 as shown in FIG. 7.

Referring to FIG. 8 and FIG. 9, the swing link component 3 comprises a rotation base 31 disposed at a lower end thereof and having a pivot portion 311 disposed at the upper end of the rotation base 31 and an armrest rotation fixing unit 32 disposed at an upper end thereof and having a pivot portion 321 disposed at the lower end of the armrest rotation fixing unit 32. Two opposing covers externally provided are pivotally fixed to a shaft 30 disposed between the two pivot portions 311, 321 of the rotation base 31 and the armrest rotation fixing unit 32 to form shell-like outer links 34. An inner link 33 parallel to the outer links 34 is pivotally connected between and slightly outside the two pivot portions 311, 321. The inner link 33 is enclosed in the two outer links 34. Hence, the armrest rotation fixing unit 32, the rotation base 31 and the inner link 33 which are disposed above and below and the outer links 34 which are disposed on the left and on the right together form a parallel four-link mechanism. If the swing link component 3 swings up and down, the armrest component 2 can still maintain its horizontal posture and be adjusted to ascend and descend. With the rotation base 31 being axially disposed at the armrest fixing unit 1, both the swing link component 3 and the armrest component 2 rotate horizontally, ascend and descend during an adjustment and positioning process. This feature, coupled with the fact that the armrest component 2 is inherently capable of horizontal rotation and forward and backward displacement, enables the armrests to undergo omnidirectional adjustment, allowing obese users and skinny users to rest their forearms on the armrests ergonomically and comfortably.

The present invention further provides a swing positioning device of the swing link component 3. The swing positioning device is disposed on the two sides of the pivot portion 321 of the armrest rotation fixing unit 32 and between the two outer links 34. Since the two swing positioning devices disposed on the two sides of the pivot portion 321 of the armrest rotation fixing unit 32, respectively, are identical, only the swing positioning device disposed on one of the two sides is described hereunder for the sake of brevity. The swing positioning device is characterized in that: the shaft 30 is centrally penetratingly disposed at the pivot portion 321 of the armrest rotation fixing unit 32; a rotation-proof recess 320 which is polygonal and has an oblong hole 324 disposed at the bottom thereof is concavely and centrally formed at the pivot portion 321 of the armrest rotation fixing unit 32; a bump portion 322 is disposed at the armrest rotation fixing unit 32, corresponds in position to the shaft 30, is positioned inside the rotation-proof recess 320, and engaged with an inner wheel component 35 capable of free rotation and having an engaging slot 352 disposed at an inner side thereof; an external wheel component 36 is received in the rotation-proof recess 320, corresponds in shape to the rotation-proof recess 320, and is engaged with the rotation-proof recess 320, such that the motion of the external wheel component 36 is restricted to sliding axially within the rotation-proof recess 320 rather than rotation; hence, matched continuous bevel gears 361, 351 which are annular and capable of meshing with each other are disposed on two opposing sides of the inner and external wheel components 35, 36, respectively.

A partial continuous positioning gear 323 is annularly disposed on a lateral side and periphery of the pivot portion 321 of the armrest rotation fixing unit 32. A partial continuous positioning gear 372 of a positioning wheel 37, which corresponds in shape to and can engage with the partial continuous positioning gear 323, is disposed outward. A rotation-proof hole 371, which is polygonal, is centrally disposed at the positioning wheel 37 and thus engaged with a rotation-proof bump 341 which is polygonal, is disposed on the inner side of the outer link 34 and corresponds in position to the shaft 30. Hence, the motion of the positioning wheel 37 is restricted to sliding relative to the rotation-proof bump 341 rather than rotation. Furthermore, the inner side of the positioning wheel 37 abuts against the external wheel component 36. A spring 38 is disposed between the positioning wheel 37 and the outer links 34. Under a resilient push force exerted by the spring 38 upon the positioning wheel 37, the positioning gears 372, 323 of the positioning wheel 37 and the pivot portion 321 of the armrest rotation fixing unit 32 always mesh with each other resiliently. Furthermore, under the resilient push force exerted by the spring 38, the bevel gears 361, 351 of the external wheel component 36 and the inner wheel component 35 always mesh with each other resiliently and thus rest on the bottom of the rotation-proof recess 320 of the pivot portion 321.

A rotation component 39 is received in the armrest rotation fixing unit 32 and centrally pivotally coupled thereto to therefore be rotatable. The outer end of the rotation component 39 extends out of the armrest rotation fixing unit 32 so as to be disposed in front of and below the armrest component 2. Two post portions 391 corresponding in position to each other extend from two sides of the inner end of the rotation component 39, respectively, and then penetrate the oblong holes 324 disposed at the bottom of the rotation-proof recess 320 of the pivot portion 321, such that the terminal ends of the post portions 391 enter and engage with the engaging slot 352 disposed at the inner wheel component 35.

Referring to FIG. 10 and FIG. 11, after the user has rested forearms on the armrest components 2 while sitting on the office chair, the user's fingers grope their way inward from below the armrest component 2 and eventually pull the rotation component 39 upward to thereby allow the inner end of the rotation component 39 to rotate. As a result, the post portion 391 at this end drives the inner wheel component 35 to rotate such that the bevel gears 351, 361 which mesh with the external wheel component 36 abut against each other; hence, the external wheel component 36 is pushed outward together with the positioning wheel 37 to thereby separate the positioning gears 372, 323 otherwise meshing with each other, such that the inner and outer links 33, 34 can swing upward and downward. At this point in time, the user can adjust the positions of the armrests to an appropriate height and then release the rotation component 39. Under the elastic force of the spring 38 or when rotated by the user's fingers, the rotation component 39 returns to its initial position to thereby drive the inner wheel component 35 to rotate backward, such that the external wheel component 36 is pressed against by the positioning wheel 37 under the elastic force of the spring 38. As a result, not only do the bevel gears 351, 361 of the inner and external wheel components 35, 36 begin to mesh with each other again, but the positioning gear 372 of the positioning wheel 37 also begins to mesh with the positioning gear 323 of the pivot portion 321 of the armrest rotation fixing unit 32 again, and in consequence the inner and outer links 33, 34 get fixed in place and thus can no longer swing, thereby allowing the armrests to be adjusted vertically.

Hence, not only does the parallel four-link mechanism of the swing link component 3 allow the armrest component 2 to maintain its horizontal posture and be adjusted to ascend and descend, but the positioning device between the outer links 34 and armrest rotation fixing unit 32 of the swing link component 3 also renders vertical adjustment operation ergonomic and convenient. Furthermore, since the inner link 33 of the swing link component 3 is hidden inside the two outer links 34, the parallel four-link mechanism of the swing link component 3 looks neat and is unlikely to clamp the user's fingers inadvertently. 

What is claimed is:
 1. An omnidirectional adjustment-oriented positioning device of an office chair armrest, comprising: an armrest component axially disposed at an upper end of an armrest fixing unit fixed at a pad laterally and at an upper end of a swing link component of a parallel four-bar linkage device so as to be rotatable, wherein the swing link component comprises a rotation base pivotally disposed on the armrest fixing unit and having an upper end provided with a pivot portion and an armrest rotation fixing unit pivotally fixed to an armrest component and having a lower end provided with a pivot portion, wherein an inner link is pivotally connected between and slightly outside the two pivot portions of the armrest rotation fixing unit and the rotation base, wherein two sides of a middle of each of the two pivot portions are pivotally fixed in place to enclose an inner link and two parallel opposing outer links; a bump portion and a rotation-proof recess being substantially polygonal and annular and having a bottom which an oblong hole is disposed on are centrally disposed on a lateral surface of the pivot portion of the armrest rotation fixing unit, wherein an inner wheel component and an external wheel component each have two opposing surfaces which annular continuous bevel gears meshing each other are disposed on and each have a lateral surface which an engaging slot corresponding in position to the oblong hole is disposed on are disposed in the rotation-proof recess, such that the inner wheel component is centrally fitted around the bump portion and thus rotatable, wherein the external wheel component corresponds in shape to the rotation-proof recess and is received therein to thereby be able to move axially only, wherein a positioning wheel abuts against an outer side of the external wheel component and is centrally provided with a polygonal rotation-proof hole, such that the rotation-proof hole gets fitted around a polygonal rotation-proof bump convexly formed and corresponding in position to the outer link, wherein a spring serving to push is disposed between the outer link and the positioning wheel, wherein an annular gear portion is disposed at the pivot portion of the armrest rotation fixing unit and the positioning wheel to effectuate the resilient abutting and meshing thereof, wherein the inner side of the positioning wheel abuts against the external wheel component resiliently, wherein a rotation component is disposed in the armrest rotation fixing unit, wherein the rotation component has its substantially central part pivotally fixed in place to thereby extend outward, wherein a post portion is convexly formed on each of the two sides at the inner end of the rotation component, wherein the post portion penetrates an oblong hole disposed on a lateral side of the armrest rotation fixing unit and thus gets engaged with the engaging slot disposed on the inner side of the inner wheel component, wherein the rotation component is rotated to drive the inner wheel component to rotate, such that the bevel gears drive the external wheel component to move outward and thus cause the positioning wheel to withdraw together with the external wheel component, wherein the positioning wheel and the pivot portion of the armrest rotation fixing unit operate to separate positioning gears otherwise meshing with each other, such that the swing link component can rotate and adjust the forward, backward and vertical positions of the armrest component. 